What caused this?

im going to say its con trails, Aircraft were looking for Scud missles durning the first months and it looks like something i saw here in Chicago right after 911.

Fighters were circling the Downtown area from the Downers grove area on the west to the mid lake on the east makning one big circle

you can also see just to the bottom left on Iraq, a straight line coming down, turning the the general area of the other effect and going right back out
I'd guess a recon plane, maybe something like this,


or, more likely, this


Flying in circles...
I appreciate the feedback. My first guess was contrails but after studying (actually over thinking) the picture I noticed that there are only 3 maybe 4 contrails that are visible. At that time during the war I would think that there would be dozens of aircraft in the sky at any one time. Of course the difference in conditions at different altitudes would affect the absense or presence of a contrail. However, as B Ozanne mentioned about the duration of a contrail under the right circumstances, given the fact that those contrails had to be sustained for quite a long time given the distance they cover, I would expect to see more that 3 or 4. I guess just the shear distance they cover, the size of the trails, the fact that they are over that wide of a range of space and that there should be alot of aircraft in that area to only see a few trails is what intrigues me the most. It is just such a fascinating image and something that I have never seen before in such a manner.